ARTIFICIAL PARTHENOGENESIS 493 



the distilled water extract being made up with boiled sea-water 

 whose concentration was not determined, but which undoubtedly 

 was hypertonic with sea-water. Hypertonicity indeed may be 

 operative in the eggs of the t^vo forms which I have examined, for 

 the concentrated sperm is probably hypertonic with respect to sea- 

 water, but in any case, it is not a factor of any consequence in 

 either Cerebratulus or Arbacia, 



Extracts of semen of Arbacia have been studied exhaustively 

 by Gies ('01) and it would be useless to repeat these well-directed 

 experiments except upon a different form. However, while Gies 

 examined alcoholic and ether extracts, which contained the phos- 

 pholipine, lecithin, this compound was not isolated so that its 

 specific effects could be studied in case any existed. There seems 

 to be a superstition hanging over lecithin^ as far as the physiology 

 of this compound is concerned, for it has been assumed to be a 

 growth-incitant (Danilewski, Desgrey and Zaky), in sex-deter- 

 mination (Russo) and variously in therapeutics. Goldfarb has 

 carefully examined the effect of lecithin obtained from hen's eggs 

 and sheep's brains by the Roaf and Edie method, which is similar 

 to Erlandsen's cold ether-aceton method, upon eggs of Arbacia, 

 the eggs first having been fertilized with their own sperm. He 

 found no evidence of acceleration in growth, that is, in the sequence 

 of segmentation stages. 



In my experiments, there were two sources of the lecithin used, 

 one being hen's yolk'' by the Hoppe-Seyler method and the other 

 ovaries and testes of Arbacia, extracted according to the following 

 method : The organs of Arbacia, were shaken with a small amount 

 of sea-water and the mass evaporated down on the water-.bath 



^ The lecithins, for there are different compounds with this designation, are 

 esters of fatty acids with phosphorus and nitrogen. The term "lipoid" which 

 adheres to them since Overton's christening, is wholly independent of their chem- 

 ical relations, for what he meant by "fat-like bodies," concerned mainly the man- 

 ner of obtaining them from their solutions, methods similar to the ones used in 

 extracting fats, namely, by ether, alcohol, benzol, etc. In saponification, glycero- 

 phosphoric acid, cholin and the constituent fatty acid (palmitic, oleic, stearic, the 

 special sort of "lecithin" being designated according to the organic acid composing 

 it), are formed. 



' I am indebted to Dr. Shiro Tashiro of the University of Chicago for the use 

 of a portion of the preparation of lecithin from hen's yolk which he was employing 

 in another set of experiments. 



